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https://www.readbyqxmd.com/read/28645004/amplified-detection-of-hepatitis-b-virus-using-an-electrochemical-dna-biosensor-on-a-nanoporous-gold-platform
#1
Laleh Enayati Ahangar, Masoud A Mehrgardi
In the present study, a nanoporous gold platform was applied for the amplified detection of Hepatitis B virus (HBV) by an electrochemical DNA biosensor. Ferrocene as a redox reporter was covalently attached to the DNA probe and its electrochemical signal was recorded as the biosensor response. For real samples, DNA was firstly extracted from blood of patients and then amplified by polymerase chain reaction (PCR) for 5cycles. Sensitivity of this biosensor was enhanced by using nanoporous gold electrode, therefore this sensor can discriminate the genome of HBV in real sample with low PCR cycles...
June 15, 2017: Bioelectrochemistry
https://www.readbyqxmd.com/read/28644821/zirconium-oxocluster-polymer-hybrid-nanoparticles-prepared-by-photoactivated-miniemulsion-copolymerization
#2
Cesare Benedetti, Paraskevi Flouda, Alice Antonello, Christine Rosenauer, Francisco F Perez-Pla, Katharina Landfester, Silvia Gross, Rafael Munoz-Espi
Photoactivated free radical miniemulsion copolymerization of methyl methacrylate (MMA) and the zirconium oxocluster Zr4O2(methacrylate)12 is used as an effective and fast preparation method of polymer/inorganic hybrid nanoparticles. The oxoclusters, covalently anchored to the polymer network, act as metal-organic cross-linkers, thus improving the thermomechanical properties of the resulting hybrid nanoparticles. Benzoin carbonyl organic compounds were used as photoinitiators. The obtained materials are compared in terms of cross-linking, effectiveness of cluster incorporation, and size distribution with the analogous nanoparticles produced by using conventional thermally-induced free radical miniemulsion copolymerization...
June 23, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28644649/role-of-a-neighbor-ion-in-the-fragmentation-dynamics-of-covalent-molecules
#3
A Méry, A N Agnihotri, J Douady, X Fléchard, B Gervais, S Guillous, W Iskandar, E Jacquet, J Matsumoto, J Rangama, F Ropars, C P Safvan, H Shiromaru, D Zanuttini, A Cassimi
Fragmentation of molecular nitrogen dimers (N_{2})_{2} induced by collision with low energy 90 keV Ar^{9+} ions is studied to evidence the influence of a molecular environment on the fragmentation dynamics of N_{2} cations. Following the capture of three or four electrons from the dimer, the three-body N_{2}^{+}+N^{m+}+N^{n+} [with (m,n)=(1,1) or (1, 2)] fragmentation channels provide clean experimental cases where molecular fragmentation may occur in the presence of a neighbor molecular cation. The effect of the environment on the fragmentation dynamics within the dimer is investigated through the comparison of the kinetic energy release (KER) spectra for these three-body channels and for isolated N_{2}^{(m+n)+} monomer cations...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28644617/dynamic-covalent-chemistry-of-carbon-dioxide-opportunities-to-address-environmental-issues
#4
Jean Septavaux, Geoffroy Germain, Julien Leclaire
Extraction and purification of basic chemicals from complex mixtures has been a persistent issue throughout the development of the chemical sciences. The chemical industry and academic research have grown over the centuries by following a deconstruction-reconstruction approach, reminiscent of the metabolism process. Chemists have designed and optimized extraction, purification, and transformation processes of molecules from natural deposits (fossil fuels, biomass, ores), in order to reassemble them into complex adducts...
June 23, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28644051/brief-overview-of-nanoparticulate-therapy-in-cancer
#5
Rajesh R Wakaskar
Nanoparticles govern an all-important role, in this day and age, in determining the tissue distribution of either hydrophobic or hydrophilic anti-cancer drugs by encapsulating them or by covalent attachment. The whole purpose is to systematically improve upon the existing anti-tumor efficacy of these drugs. Selective delivery of these chemotherapeutic agents to the compromised or diseased tissue is the key to avoid any potential toxicity problems. Certain types of nanoparticles, through various mechanisms such as active targeting or reversing multi-drug resistance, display immense potential in adding to the existing anti-tumor efficacy profile...
June 23, 2017: Journal of Drug Targeting
https://www.readbyqxmd.com/read/28643834/understanding-the-remarkable-luminescence-enhancement-via-sio2-coating-on-tio2-eu-3-nanofibers
#6
Meiqi Chang, Yanhua Song, Ye Sheng, Jie Chen, Haifeng Zou
TiO2:Eu(3+) nanofibers diameters can be tuned by changing the mixed solvent ratio are synthesized via the electrospinning technique. Concentration quenching phenomena and the relationship of the PL intensity ratio I((5)D0-(7)F2)/I((5)D0-(7)F1) with the Eu doping concentration are discussed. Notably, the luminescence intensity is enhanced by about 7.8 fold by coating SiO2 gel layer on the TiO2:Eu(3+) nanofibers, which is successfully performed via a sol-gel process followed by calcination. Furthermore, these fibers are characterized systematically via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28643695/highly-fluorescent-and-superparamagnetic-nanosystem-for-biomedical-applications
#7
Mariana P Cabrera, Paulo E Cabral Filho, Camila M C M Silva, Rita M Oliveira, Carlos F G C Geraldes, M Margarida C A Castro, Benilde F O Costa, Marta S C Henriques, José A Paixão, Luiz B Carvalho, Beate S Santos, Fernando Hallwass, Adriana Fontes, Giovannia A L Pereira
This work reports on highly fluorescent and superparamagnetic bimodal nanoparticles (BNPs) obtained by a simple and efficient method as probes for fluorescence analysis and/or contrast agents for MRI. These promising BNPs with small dimensions (ca. 17 nm) consist of superparamagnetic iron oxide nanoparticles (SPIONs) covalently bound with CdTe quantum dots (ca. 3 nm). The chemical structure of the magnetic part of BNPs is predominantly magnetite, with minor goethite and maghemite contributions, as shown by Mössbauer spectroscopy, which is compatible with the x-ray diffraction data...
July 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28643432/the-penetration-and-phenotype-modulation-of-smooth-muscle-cells-on-surface-heparin-modified-poly-%C3%AE%C2%B5-caprolactone-vascular-scaffold
#8
Jie Cao, Xue Geng, Juan Wen, Qingxuan Li, Lin Ye, Aiying Zhang, Zengguo Feng, Lianrui Guo, Yongquan Gu
The tubular porous poly(ε-caprolactone)(PCL) scaffold was fabricated by electrospinning. After then, the scaffold's surface was firstly eroded by hexyldiamine to endow amine group, and heparin was covalently grafted to the surface to get surface heparin modified scaffold(ShPCL scaffold). It was found that ShPCL scaffold can induce smooth muscle cells (SMCs) to penetrate the scaffold surface, while the SMCs can't penetrate the surface of PCL scaffold. Subsequently, the rabbit SMCs were seeded on the ShPCL scaffold and cultured for 14 days...
June 23, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28641436/doping-as-a-means-to-probe-the-potential-dependence-of-dopamine-adsorption-on-carbon-based-surfaces-a-first-principles-study
#9
Anja Aarva, Tomi Laurila, Miguel A Caro
In this work, we study the adsorption characteristics of dopamine (DA), ascorbic acid (AA), and dopaminequinone (DAox) on carbonaceous electrodes. Our goal is to obtain a better understanding of the adsorption behavior of these analytes in order to promote the development of new carbon-based electrode materials for sensitive and selective detection of dopamine in vivo. Here we employ density functional theory-based simulations to reach a level of detail that cannot be achieved experimentally. To get a broader understanding of carbonaceous surfaces with different morphological characteristics, we compare three materials: graphene, diamond, and amorphous carbon (a-C)...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28641426/assessment-of-two-hybrid-van-der-waals-density-functionals-for-covalent-and-non-covalent-binding-of-molecules
#10
Kristian Berland, Yang Jiao, Jung-Hoon Lee, Tonatiuh Rangel, Jeffrey B Neaton, Per Hyldgaard
Two hybrid van der Waals density functionals (vdW-DFs) are developed using 25% Fock exchange with (i) the consistent-exchange vdW-DF-cx functional [K. Berland and P. Hyldgaard, Phys. Rev. B 89, 035412 (2014)] and (ii) with the vdW-DF2 functional [K. Lee et al., Phys. Rev. B 82, 081101 (2010)]. The ability to describe covalent and non-covalent binding properties of molecules is assessed. For properties related to covalent binding, atomization energies (G2-1 set), molecular reaction energies (G2RC set), and ionization energies (G21IP set) are benchmarked against experimental reference values...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28641421/effective-empirical-corrections-for-basis-set-superposition-error-in-the-def2-svpd-basis-gcp-and-dft-c
#11
Jonathon Witte, Jeffrey B Neaton, Martin Head-Gordon
With the aim of mitigating the basis set error in density functional theory (DFT) calculations employing local basis sets, we herein develop two empirical corrections for basis set superposition error (BSSE) in the def2-SVPD basis, a basis which-when stripped of BSSE-is capable of providing near-complete-basis DFT results for non-covalent interactions. Specifically, we adapt the existing pairwise geometrical counterpoise (gCP) approach to the def2-SVPD basis, and we develop a beyond-pairwise approach, DFT-C, which we parameterize across a small set of intermolecular interactions...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28641222/theoretical-evaluation-on-selective-adsorption-characteristics-of-alkali-metal-based-sorbents-for-gaseous-oxidized-mercury
#12
Hongjian Tang, Yufeng Duan, Chun Zhu, Tianyi Cai, Chunfeng Li, Liang Cai
Alkali metal-based sorbents are potential for oxidized mercury (Hg(2+)) selective adsorption but show hardly effect to elemental mercury (Hg(0)) in flue gas. Density functional theory (DFT) was employed to investigate the Hg(0) and HgCl2 adsorption mechanism over alkali metal-based sorbents, including calcium oxide (CaO), magnesium oxide (MgO), potassium chloride (KCl) and sodium chloride (NaCl). Hg(0) was found to weakly interact with CaO (001), MgO (001), KCl (001) and NaCl (001) surfaces while HgCl2 was effectively adsorbed on top-O and top-Cl sites...
June 12, 2017: Chemosphere
https://www.readbyqxmd.com/read/28641210/comparative-analysis-of-polyspecificity-of-the-endogenous-trna-synthetase-of-different-expression-host-towards-photocrosslinking-amino-acids-using-an-in-silico-approach
#13
Nadarajan Saravanan Prabhu, Hyungdon Yun
Photo-induced covalent crosslinking has emerged as the powerful strategy for analyzing and characterizing the protein-protein interaction and mapping protein 3D conformations. In the last decades, a number of photocrosslinking amino acids have been reported but only a few have been efficiently utilized for photocrosslinking purposes. Recently, incorporation of diazirine containing photoactivatable analogs such as photo-methionine, photo-leucine, photo-isoleucine and photo-lysine into target proteins were accomplished in live cells (Human A549cells, HEK 293) by depleting corresponding natural amino acid and supplementing these analogs in the medium...
June 8, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28640997/from-1d-polymers-to-2d-polymers-preparation-of-free-standing-single-monomer-thick-two-dimensional-conjugated-polymers-in-water
#14
Na Zhang, Taisheng Wang, Xing Wu, Chen Jiang, Taiming Zhang, Bangkun Jin, Hengxing Ji, Wei Bai, Ruke Bai
Recently, investigation on two-dimensional (2D) organic polymers has been made a great progress and conjugated 2D polymers already play a dynamic role in both academic and practical applications. However, a convenient, non-interfacial approach to obtain single-layer 2D polymers in solution, especially in aqueous media remains challenging. Herein, we present a facile, highly efficient and versatile "1D to 2D" strategy for preparation of free-standing single-monomer-thick conjugated 2D polymers in water without any aid...
June 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28640638/enzyme-mediated-conversion-of-fad-to-8-formyl-fad-in-formate-oxidase-results-in-modified-cofactor-with-enhanced-catalytic-properties
#15
John M Robbins, Michael G Souffrant, Donald Hamelberg, Giovanni Gadda, Andreas S Bommarius
Flavins, including flavin adenine dinucleotide (FAD), are fundamental catalytic cofactors responsible for the redox functionality of a diverse set of proteins. Alternatively, modified flavin analogues are rarely found in nature as their incorporation typically results in inactivation of flavoproteins, thus leading to the disruption of important cellular pathways. Here, we report that the fungal flavoenzyme formate oxidase (FOX) catalyzes the slow conversion of non-covalently bound FAD to 8-formyl FAD (8-fFAD), and that this conversion results in a nearly 10-fold increase in formate oxidase activity...
June 22, 2017: Biochemistry
https://www.readbyqxmd.com/read/28640515/carbon-dots-as-fillers-inducing-healing-self-healing-and-anticorrosion-properties-in-polymers
#16
Cheng Zhu, Yijun Fu, Changan Liu, Yang Liu, Lulu Hu, Juan Liu, Igor Bello, Hao Li, Naiyun Liu, Sijie Guo, Hui Huang, Yeshayahu Lifshitz, Shuit-Tong Lee, Zhenhui Kang
Self-healing is the way by which nature repairs damage and prolongs the life of bio entities. A variety of practical applications require self-healing materials in general and self-healing polymers in particular. Different (complex) methods provide the rebonding of broken bonds, suppressing crack, or local damage propagation. Here, a simple, versatile, and cost-effective methodology is reported for initiating healing in bulk polymers and self-healing and anticorrosion properties in polymer coatings: introduction of carbon dots (CDs), 5 nm sized carbon nanocrystallites, into the polymer matrix forming a composite...
June 22, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28640482/organogelator-cellulose-composite-for-practical-and-eco-friendly-marine-oil-spill-recovery
#17
Kana M Sureshan, Annamalai Prathap
Marine oil-spills pose serious threats to the ecosystem and economy. There is much interest in developing sorbents that can tackle such spills. We have developed a novel sorbent by impregnating cellulose pulp with a sugar-derived oleogelator, 1,2:5,6-di-O-cyclohexylidene-mannitol. The gelator molecules mask the surface-exposed hydroxyl groups of cellulose fibrils by engaging them in H-bonding and expose their hydrophobic parts making the fibers temporarily hydrophobic (water contact-angle 110°). This sorbent absorbs oil effectively, selectively and instantly from oil-water mixtures due to its hydrophobicity...
June 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28640439/skin-inspired-multifunctional-autonomic-intrinsic-conductive-self-healing-hydrogels-with-pressure-sensitivity-stretchability-and-3d-printability
#18
Mohammad Ali Darabi, Ali Khosrozadeh, Rene Mbeleck, Yuqing Liu, Qiang Chang, Junzi Jiang, Jun Cai, Quan Wang, Gaoxing Luo, Malcolm Xing
The advent of conductive self-healing (CSH) hydrogels, a class of novel materials mimicking human skin, may change the trajectory of the industrial process because of their potential applications in soft robots, biomimetic prostheses, and health-monitoring systems. Here, the development of a mechanically and electrically self-healing hydrogel based on physically and chemically cross-linked networks is reported. The autonomous intrinsic self-healing of the hydrogel is attained through dynamic ionic interactions between carboxylic groups of poly(acrylic acid) and ferric ions...
June 22, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28640222/albumin-and-hyaluronic-acid-coated-superparamagnetic-iron-oxide-nanoparticles-loaded-with-paclitaxel-for-biomedical-applications
#19
Elena Vismara, Chiara Bongio, Alessia Coletti, Ravit Edelman, Andrea Serafini, Michele Mauri, Roberto Simonutti, Sabrina Bertini, Elena Urso, Yehuda G Assaraf, Yoav D Livney
Super paramagnetic iron oxide nanoparticles (SPION) were augmented by both hyaluronic acid (HA) and bovine serum albumin (BSA), each covalently conjugated to dopamine (DA) enabling their anchoring to the SPION. HA and BSA were found to simultaneously serve as stabilizing polymers of Fe₃O₄·DA-BSA/HA in water. Fe₃O₄·DA-BSA/HA efficiently entrapped and released the hydrophobic cytotoxic drug paclitaxel (PTX). The relative amount of HA and BSA modulates not only the total solubility but also the paramagnetic relaxation properties of the preparation...
June 22, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28640205/lectins-from-mycelia-of-basidiomycetes
#20
REVIEW
Valentina E Nikitina, Ekaterina A Loshchinina, Elena P Vetchinkina
Lectins are proteins of a nonimmunoglobulin nature that are capable of specific recognition of and reversible binding to the carbohydrate moieties of complex carbohydrates, without altering the covalent structure of any of the recognized glycosyl ligands. They have a broad range of biological activities important for the functioning of the cell and the whole organism and, owing to the high specificity of reversible binding to carbohydrates, are valuable tools used widely in biology and medicine. Lectins can be produced by many living organisms, including basidiomycetes...
June 22, 2017: International Journal of Molecular Sciences
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